JPH01186350A - Recording method - Google Patents

Abstract

PURPOSE:To prevent the reverse transfer of a transferred ink pattern to other color ink, in selectively transferring a second hue ink after the transfer of a first hue ink by applying potential having polarity opposite to that of pattern like potential to the second hue ink on the side of a medium to be transferred. CONSTITUTION:A first ink 2a is transferred to an intermediate transfer roll 6 by a first image forming unit 7a to form a first hue ink pattern 22a and, subsequently, a second ink pattern 22b is selectively formed from a second image forming unit 7b so as to be registered with the first ink pattern 22a. At this time, since the ink 2a constituting the first ink pattern 22a is gelled by applying bias voltage between the intermediate transfer roll 6 and an ink support roll 1b, the inverse transfer of the first ink 2a to the second ink 2b is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a recording method that allows recording in multiple colors on a recording medium at low cost using ink that can be tackified by electricity.

BACKGROUND ART Today, among recording methods for information processing, various formats have been developed that can record on plain paper, such as impact printers, electrophotography, laser beam printers, and thermal transfer printers.

Among these, thermal transfer type recording devices are widely used because they have low noise and can be miniaturized. This recording method uses an ink ribbon made by coating hot-melt ink on a base sheet, heats the ink ribbon in an image pattern with a recording head, and transfers the molten ink to recording paper. This has advantages such as low noise, relatively small device size, and low device cost. Further, in this thermal transfer method, color recording is also possible by using ink ribbons of multiple colors.

However, in the conventional thermal transfer method described above, when manufacturing an ink ribbon, it is necessary to apply heat-melting ink onto a heat-resistant base sheet in a complicated process, and this ink ribbon cannot be used for one recording. There were problems such as high running costs because the devices had to be disposed of only after being used.

As a means to solve the above-mentioned problems, the present applicant has proposed that a fluid ink whose viscosity can be changed by applying energy is transferred in the form of a film using an ink transfer means, and this ink is energized to form an image pattern. proposed a recording method in which an ink image with adhesive properties is formed and this ink image is transferred onto a recording medium (Japanese Patent Application No. 175191/1982).

According to this recording method, it is not necessary to use an ink ribbon as in the conventional thermal transfer method, and only the ink that forms an ink image is transferred to the recording medium, and the ink that does not form an ink image can be repeatedly used. Although this method enables low-cost recording, it is desired that such a recording method also be able to support multi-color printing.

OBJECTS OF THE INVENTION An object of the present invention is to provide a recording method that makes it possible to produce high-quality images in multiple colors while taking advantage of the characteristics of the above-mentioned recording method of the present applicant.

Another object of the present invention is to provide a color recording method capable of transferring inks of multiple colors onto the same transfer medium.

Summary of the Invention As a result of extensive research, the present inventors have found that after transferring the ink of the first tone, when further transferring the ink of the second tone to the transfer medium, the tackiness changes in the opposite direction to that during image formation. Applying to the second ink a bias potential difference that gives
It has been found that the reverse transfer of the first ink to the second ink can be prevented, and it is possible to achieve suitable multi-color printing.

The recording method of the present invention is based on the above-mentioned knowledge, and more specifically, it uses an ink that is substantially non-adhesive and can be imparted with tackiness by electricity, and is supported on an ink carrier. A recording method in which a patterned potential is applied to the ink, and the ink having an adhesive pattern is selectively transferred to a transfer medium according to the potential, the ink having a first color tone. After the ink is transferred to the transfer medium, when selectively transferring the ink having the second color tone to the transfer medium, a potential having a polarity opposite to the patterned potential is applied from the transfer medium side to the transfer medium. It is characterized in that it is applied to ink having two tones.

Hereinafter, the present invention will be described in further detail with reference to the drawings as necessary. In the following description, "r%" representing the quantitative ratio.
"and 1 part" are based on weight unless otherwise specified.

DETAILED DESCRIPTION OF THE INVENTION FIG.
The basic configuration of the recording apparatus will be explained with reference to the drawings.

First, referring to FIG. 1, an ink carrying roll 1a serving as an ink carrying means is rotatable in the direction of arrow A (counterclockwise) while transferring the first fluid ink 2a contained in the ink container 3a. It is set in.

The ink 2a is, for example, a gel-like ink that has fluid film properties and is substantially non-tacky under normal conditions, but becomes sticky when electrical energy is applied. Consisting of Therefore, when the ink carrying roll 1a rotates in the direction of arrow A, the ink 2a is transferred in the direction of arrow A to the surface of the ink carrying roll 1a with a constant layer thickness by the coating member 4a.

An ink layer 21a made of ink 2a formed in a certain layer on the surface of the ink carrying roll 1a is applied with electrical energy in an image pattern by a recording electrode 5a serving as an energy applying means, and this energy application causes i, Selective adhesiveness is imparted to the ink 2a. The selectively adhesive ink 2a is then transferred to an intermediate transfer roll 6, which is a transfer medium, and rotates in the direction of arrow B (clockwise)''.
The ink pattern is transferred to the surface of the roll 60 by contacting with
22a is formed.

On the other hand, the ink 2a that has not been transferred to the intermediate transfer roll 6 is re-accommodated in the ink container 3a as the ink carrying roll 1 rotates in the direction of arrow A.
They are stirred and mixed inside and then reused.

The above-mentioned ink carrying roll 1a and ink container 3a,
A first electrode comprising a recording electrode 5a and a coating member 4a.
On the surface side of the intermediate transfer roll 6 on the downstream side of the image forming unit 7a, image forming units 7b and 7C having the same configuration as the first image forming unit 7a are respectively arranged according to the desired ink tone. . The ink containers 3b and 3c of the second image forming unit 7b and the third image forming unit 7c contain ink 2b of a second color tone and ink 2c of a third color tone, respectively.

Next, a multicolor recording method using the recording apparatus shown in FIG. 1 will be explained.

First, as described above, the first ink 2a is applied to the first ink 2a by the first image forming unit 7a at the first ink transfer position where the ink carrying roll 1a of the first image forming unit 7a and the intermediate transfer roll 6 face each other. The ink pattern 22a of the first color tone is formed by being transferred to the intermediate transfer roll 6.

Next, as the intermediate transfer roll 6 rotates in the direction of arrow B, the ink pattern 22a reaches a second ink transfer position where the intermediate transfer roll 6 and the ink carrying roll 1b of the second image forming unit 7b face each other. At this second ink transfer position, ink 2 of the second color tone is selectively applied from the second image forming unit 7b onto the intermediate transfer roll 6 in alignment with the first ink pattern 22a.
b is transferred to form a second ink pattern 22b. The second ink pattern 22b may be formed to overlap the first ink pattern 22a in whole or in part.

When forming this second ink pattern 22b,
By applying a bias voltage between the intermediate transfer roll 6 and the ink carrying roll 1b, the first ink pattern 22a is
Since the ink 2a constituting the second ink 2a is gelled, its reverse transfer to the second ink 2b is prevented.

Ink patterns 22a and 2 formed as described above
2b and registration, the ink 2c of the third tone is selectively transferred from the image forming unit 7c onto the intermediate transfer roll 6 at the third ink transfer position in the same way, and a third ink pattern 22c is formed. Ru. All or part of this third ink pattern 22c may be formed overlapping the first and/or second ink patterns 22a, 22b.

Also when forming this third ink pattern 22c,
The first ink pattern 22 is formed by applying a bias voltage between the intermediate transfer roll 6 and the ink carrying roll 1c described above.
Reverse transfer of the second ink pattern a and the second ink pattern 22b to the third ink 2c is prevented.

The three-color ink pattern 22a formed in this way,
22b and 22c are conveyed in the direction of the arrow between the intermediate transfer roll 6 and the platen roll 7, which is a transfer means that is provided in pressure contact with the intermediate transfer roll 6 and is rotatable in the direction of arrow C (counterclockwise). - is transferred onto a recording medium 8 (made of plain paper, plastic sheet, etc., for example), and a multicolored transferred recorded image 23 is formed.

In the embodiment shown in FIG. 1, as described above, the ink pattern 22 on the intermediate transfer roll 6 is applied with a bias voltage (i.e., energized from the recording electrode 5) to reduce the stickiness of the ink 2 constituting the ink pattern. A voltage that causes a change in tack that is opposite to the change in tack based on the voltage is applied.

In this way, by applying a bias voltage to the ink 2 between the ink carrier 1 and the transfer medium 6 as electrically conductive poles, the first ink pattern 22a that has been transferred to the transfer medium 6 can be This prevents reverse transfer to the 2 ink 2b.

Application of such a bias promotes gelation of the non-image areas of the second ink 2b, which also has the effect of making it more difficult to adhere the first ink pattern 22a. In order to prevent defective transfer to the intermediate transfer roll 6 due to regelation of the image area of the second ink 2b due to the application of this bias, this bias voltage is set, for example, to the potential of the ink carrier at 0 (reference). If the potential of the current-carrying head 5b that applies a patterned voltage is +aV, and the potential of the transfer medium 6 is -bv, then a
>b is preferable, and further preferably, the absolute value of b is approximately 1/10 to 8/10 times that of a.

Similarly, when using ink 2 that becomes a sol at the negative electrode and gels at the positive electrode, for example, the ink carrier is set to OV, the current-carrying head that applies a voltage in a pattern is set to -aV, and the potential of the recording medium to be transferred is set to +bv. In this case, it is preferable that a>b.

In this way, the intermediate transfer roll 6 and the ink carrying roll la
, Ib, or 1c is preferably smaller than the potential between these ink supporting rolls and the recording electrode 5. Further, when the ink carrying roll is set to OV (reference), the potentials of the recording electrode 5 and the intermediate transfer roll 6 have opposite polarities.

It is preferable to apply a bias voltage also to the first ink carrying roll 1a as described above from the viewpoint of controlling changes in tackiness due to temperature changes.

Next, the configuration of each part of the recording apparatus will be explained in detail.

The ink carrying roll 1 is made of a conductive material that can transfer fluid ink 2, which will be described later, by forming a film on its surface.
In the embodiment described above, a cylindrical material made of metal such as stainless steel, aluminum, or iron, and preferably plated with gold, platinum, rhodium, etc., is preferably used. Among these, platinum plating is preferred from the viewpoint of durability.

Next, the fluid ink 2 transferred by the ink carrying roll 1 will be explained. This ink 2 has a fluid film-forming property that flows under the application of a certain external force and forms an ink film. Specifically, as the ink carrying roll rotates 10 times, an ink layer is formed on the surface of the roll 1 and transported. Further, it is preferable that the ink 2 has a property of being able to restore its adhesiveness over time after being cut by an external force. That is, it is preferable that the ink lumps have a property such that when they come into contact with each other, the interface disappears and they become one piece.

The ink 2 having the above-mentioned properties may be an ink having a gel state in a broad sense in which the solvent is held by a cross-linked structure substance, or particles (preferably having a particle size of 0.5 cps) in a relatively high viscosity (preferably 5000 cps or more) solvent. 01~100μm
1 to 20 μm) is preferably used. Inks having properties of both gel-like inks and sludge-like inks are more preferably used.

Specific examples of this ink 2 include Japanese Patent Application No. 5T-175191 or No. 62-3 previously filed by the present applicant.
Inks described in No. 6904 and the like are preferred.

Such ink 2 has fluid film-forming properties, but is substantially non-adhesive, and has a property of becoming adhesive when electrical energy is applied.

In addition, "stickiness" here refers to selective stickiness,
When the ink 2 is brought into contact with an object such as the intermediate transfer roll 6, a portion of the ink 2 separates from the entire ink and adheres to the object, regardless of whether the entire ink is sticky or not.

Therefore, in the ink layer 21 formed on the surface of the ink carrying roll 1, when no energy is applied, the ink 2 is transferred to another medium such as the intermediate transfer roll 6.
Even if it comes into contact with the intermediate transfer roll 6, the image is not substantially transferred to the intermediate transfer roll 6. This is thought to be because in gel ink, the solvent is held in a crosslinked structure (except for a small amount of solvent), so the ink is not transferred to the intermediate transfer roll 6.
In addition, in the case of ink in a sludge state, it is thought that because the particles are closely arranged at the interface, the solvent portion of the ink becomes difficult to come into contact with the intermediate transfer roll 6 and is not transferred to the intermediate transfer roll 6.

On the other hand, when electrical energy is applied to the gel-like ink or sludge-like ink, the crosslinked structure of the gel-like ink and the particle arrangement state of the sludge-like ink change. It is thought that these emotional inks are given tackiness in response to the application of electrical energy.

Furthermore, when the ink 2 is coated on the ink carrying roll 1, it has properties as a plastic body, and conversely, after it is applied with energy by the energy applying means 5 and reaches the intermediate transfer roll 6, it becomes an elastic body. It is preferable to have the following properties.

For this reason, in the embodiments described above, as the ink 2, one having a certain degree of viscoelasticity (complex elasticity having an elastic term and a viscous term) is preferably used.

The thickness of the layer 21 of the ink 2 formed on the surface of the ink carrying roll 1 depends on the emotionality or viscosity of the ink 2, the material or roughness of the surface of the ink carrying roll 1, or the thickness of the ink 2 layer 21 formed on the surface of the ink carrying roll 1. Although it varies depending on the rotation speed, etc., at the ink transfer position where the ink carrying roll 1 faces the intermediate transfer roll 6, the rotation speed is approximately 0.1 to 5 mm, more preferably 0.
．． It is preferably about 5 to 3 mm.

If the thickness of this ink layer 2a is less than 0.1 mm,
It becomes difficult to form a uniform ink layer on the ink carrying roll 1, and if the layer thickness exceeds 5 mm, it becomes difficult to transport the ink 2 while keeping the surface layer of the ink layer 21 at a uniform circumferential speed. It becomes difficult to apply electricity from the energy applying means 5 to the ink carrying roll 1 via the ink 2.

Next, as the energy applying means 5, a recording electrode 5 is used to apply electrical energy.

As shown in the schematic perspective view of FIG. 2, the recording electrode 5 is formed by arranging a plurality of electrode elements 52 made of metal such as copper in a line on a base 51 made of glass epoxy, alumina, glass, etc. An insulating film 53 made of polyimide or the like is provided on a portion of the electrode element 52 other than the tip, that is, a portion other than the portion that contacts the ink 2. This embodiment (first
In the case shown in FIG. 1, the ink carrying roll 1 is grounded so that current can be passed between the roll 1 and the electrode element 52 via the ink 2. Note that the electrode element 5
The portion exposed from the insulating film 53 of No. 2 is coated with gold, platinum,
It is preferable to plate with rhodium or the like, and from the viewpoint of durability, platinum plating is more preferable.

When the recording electrode 5 is arranged, it is preferable to arrange it so that the electrode element 52 is slightly submerged in the ink layer 21 formed on the ink carrying roll 1, as shown in FIG. The amount of retraction is set to about 0 to 1 mm, more preferably about 0.1 to 0.5 mm. By slightly immersing it in the ink layer in this way, the energizing effect can be further enhanced. Incidentally, even if the electrode element 52 is immersed in the ink layer as described above, there is no problem since the ink 2 normally has viscoelasticity.

Further, when the electrode element 52 is immersed in the ink layer as described above, the end surface of the substrate 51 and the electrode element 52 in FIG.
It is preferable that the difference in level between the end face and the end face is in the range of about 0 to 100 μm, and if possible, it is desirable that both end faces have no step difference and are formed on the same surface. This is because if the step difference is large, the ink image formed by energization from the electrode element 52 may be rubbed and destroyed by the end surface of the substrate 51, causing disturbances in the recorded image.

For example, when guar gum is used as the crosslinked structure material of the ink 2 and is used crosslinked with boric acid ions, the amount of current applied to the recording electrode 5 is determined to be enough to destroy this crosslinked structure and cause an electrochemical change. The amount of current required is sufficient. Therefore, the amount necessary to transfer electrons to the crosslinking agent, which is normally added in a small amount of several hundred ppm to ink 2, is sufficient, and when applying thermal energy with a thermal head in a thermal transfer recording method, etc. Approximately 1/1 compared to the current amount of
Application of a low energy of about 10 is sufficient. By applying energy from the recording electrode 5 in this manner, the ink 2 becomes sticky.

Next, the intermediate transfer roll 6 is used to transfer the ink that has been given adhesiveness by applying energy to form an ink pattern 22, and in the embodiment shown in FIG. It is disposed to the left or above the ink carrying roll 1 with a distance of preferably about 0.1 to 3 m+n from the surface of the carrying roll 1, and is in contact with the ink layer 21 formed on the roll 1, as shown in the figure. It is configured to be rotatable in the direction of arrow B by means of a drive means that does not have the same structure.

The material constituting the surface of the intermediate transfer roll 6 is as follows:
It is possible to use the same material as the material forming the surface of the ink carrying roll 1.

Next, the platen 7 constitutes a transfer means for transferring the ink pattern 22 transferred and formed on the intermediate transfer roll 6 to the recording medium 8, and has a nitrile rubber or silicone rubber on a metal shaft. A platen roll 7 formed of a cylinder or the like is used. In this embodiment, such a platen roll 7 is pressed against the intermediate transfer roll 6 by a spring or the like (not shown) with a pressing force of about 0.1 to 5 kgf/cm, and as the intermediate transfer roll 6 rotates, the arrow By rotating in the C direction, the recording medium 8 is conveyed in the direction of the arrow by cooperation with the intermediate transfer roll 6, and the ink pattern 22 formed on the intermediate transfer roll 6 is transferred to the recording medium 8. It is configured to be transcribed.

If the fixability of the ink image 23 is insufficient, a known fixing means (not shown) such as heating or pressure may be provided on the recording medium downstream of the ink image transfer position 8. good.

In the embodiment shown in FIG. 1, the intermediate transfer roll 6 is used as the intermediate transfer medium, but it may also be used by transporting a conductive film in one direction, similar to the ink carrying means, or it may be used as an endless transfer medium. It may also be used in the form of a belt.

Alternatively, the ink may be directly transferred from the ink carrying roll 1 to the recording medium 8 without providing such an intermediate transfer medium.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example <First ink> (8 copper tetra-4 (octadecyl sulfonamide) phthalocyanine, color index group - Cl74160
X-copper phthalocyanine pigment described as. ) After uniformly mixing the ingredients of the above recipe while heating to 7' Ot, add component B and leave it at room temperature to prepare a gel-like first ink (cyan color) used in the recording method of the present invention. did. - Second ink> Except that a magenta colorant (2,9-dimethyl-substituted quinacridone and anthraquinone dye listed as Cl60710 in the color index) was used instead of the cyan colorant used in the first ink. A magenta second ink was obtained in the same manner as the first ink.

<Third ink> Instead of the cyan colorant used in the first ink,
Yellow was prepared in the same manner as in the first ink 2, except that a colorant (cyanilide yellow, 3,3-dichloropenzidine acetoacetanilide, a monoazo pigment listed as C112700 in the color index) was used. A third color ink was obtained.

The cyan first ink 2a thus obtained is placed in the ink container 3a of the first image forming unit 7a, the magenta second ink 2b is placed in the ink container 3b of the second image forming unit 7b, and the yellow ink is placed in the ink container 3b of the second image forming unit 7b. The third ink 2c was put into the ink container 3β of the third image forming unit 7c, and an image forming test was performed using the recording apparatus shown in FIG.

That is, referring to FIG. 1, ink carrying rolls 1a, 1
b. The IC used was a stainless steel roll with a diameter of 40 mm plated with platinum. The intermediate transfer roll 6 has a hard chrome plated surface and has a diameter of 40 mm.
mm iron roll is used, and the ink carrying roll la
, lb, and the IC were set to 2 mm.

As the platen roll 7, a roll having a 5 mm thick silicone rubber layer on a 10 mm diameter iron roll is used, and the intermediate transfer roll 6 has a weight of 0.1 kg.
A pressure of f/cm was applied and the roller was rotated at the same speed as the intermediate transfer roll 6.

In the above configuration, the intermediate transfer roll 6 is rotated at a rotation speed of about 18 r.
pm in the direction of arrow B, and rotated the ink-carrying Ronil 1 in the direction of arrow A at approximately 18 pm, the inks 2a, 2b, and 2c change to the state of the ink layer 21 due to the action of the coating member 4. If no energy is applied to the ink layer 21 from the recording electrode 5 while the ink layer 21 is formed in a layer with a thickness of 2 mm on the surface of the ink carrying roll 1, all of the ink is transferred to the intermediate transfer roll 6. It didn't bother me.

Further, as shown in FIG. 2, the surface of each ink layer 21 is formed by using a recording electrode 5 in which an electrode element 52 is exposed in an area of 100 μm x 100 μm only at the tip, and this recording electrode 5 is used as an anode and an ink carrying roll. 1a, 1b and IC as cathodes, 20V via ink 2 according to the image signal,
Applying a pulse (patterned voltage) of 1 m SeC,
Further, when a bias voltage of IOV was applied using the intermediate transfer roll 6 as a cathode and the ink carrying rolls 1a, 1b and IC as anodes, the fluid ink was transferred at the first, second and third ink transfer positions, resulting in the above-mentioned effect. Ink pattern 22a consisting of three colors of ink corresponding to patterned voltages
, 22b and 22c were formed on the intermediate transfer roll 6, and these ink patterns were further transferred to the recording medium 8 made of plain paper at the ink image transfer position, thereby obtaining a clear transferred recorded image 23.

At this time, the first ink pattern 22a at the second ink transfer position is reversely transferred to the second ink 2b, or the first ink pattern 22a to the second ink pattern at the third ink transfer position is
No reverse transfer of the ink pattern 22b to the third ink 2C was observed, and the ink pattern 22 to the transferred recorded image 23 were obtained as clear full-color images.

Comparative Example An image forming test was carried out in the same manner as in the example, except that no bias voltage was applied between the intermediate transfer roll 6 and the ink carrying rolls la, lb, or IC in the example. However, the first ink pattern 22a is reversely transferred to the second ink 2b at the second ink transfer position, and the second ink pattern 4 turns 2 at the third ink transfer position
2b to the third ink 2c occurred, and only a transferred recorded image 23 with almost no first ink pattern 22a and second ink pattern 22b was obtained.

Effects of the Invention As described above, according to the present invention, by applying a bias potential that reduces the ink tackiness on the side of the transfer medium, the ink pattern that has been selectively transferred to the transfer medium can be removed. Reverse transfer to color ink is prevented, allowing high-quality multicolor recording.

[Brief explanation of the drawing]

- FIG. 1 is a schematic side sectional view showing an example of a recording device suitably used in the recording method of the present invention, and FIG. 2 is a schematic perspective view showing an example of the configuration of a recording electrode used in the above device. 1... Ink carrying roll 2... Fluid ink. 3... Ink container 4... Ink multi-coach, Ink means 5... Recording electrode 51... Substrate 52... Electrode element 53... Insulating coating 6... Intermediate transfer roll 7...・Platen 8...Representative diagram of recording medium: Figure 1 Figure 1

Claims (1)

[Claims] Using an ink that has substantially no tackiness and can be tackified by applying electricity, a patterned potential is applied to the ink supported on an ink carrier, and the ink is A recording method for selectively transferring the ink provided with an adhesive pattern according to an electric potential to a transfer medium, the method comprising: transferring the ink having a first tone to the transfer medium; When selectively transferring the ink having a color tone to the transfer medium, a potential having a polarity opposite to the patterned potential is applied from the transfer medium side to the ink having the second tone. Recording method.